From dacc355ec3267f43135400b88fe3ad814ca894c0 Mon Sep 17 00:00:00 2001
From: Kristen Wright <kwright@mozilla.com>
Date: Wed, 21 Aug 2019 10:11:04 +0000
Subject: [PATCH] Bug 1572505 - Convert network.dns.disablePrefetchFromHTTPS to
 static pref. r=smaug,njn

Converts network.dns.disablePrefetchFromHTTPS to a static pref. Though the original VarCache pref default to `false`, it looks like the intended value is `true`. (see comment #0 in bug 1572505)

Differential Revision: https://phabricator.services.mozilla.com/D42737

--HG--
extra : moz-landing-system : lando
---
 dom/base/Document.cpp                    | 6 +++---
 dom/html/nsHTMLDNSPrefetch.cpp           | 8 --------
 modules/libpref/init/StaticPrefList.yaml | 5 +++++
 3 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/dom/base/Document.cpp b/dom/base/Document.cpp
index 4daf897f483b..4ec241cce397 100644
--- a/dom/base/Document.cpp
+++ b/dom/base/Document.cpp
@@ -34,6 +34,7 @@
 #include "mozilla/StaticPrefs_dom.h"
 #include "mozilla/StaticPrefs_full_screen_api.h"
 #include "mozilla/StaticPrefs_layout.h"
+#include "mozilla/StaticPrefs_network.h"
 #include "mozilla/StaticPrefs_page_load.h"
 #include "mozilla/StaticPrefs_plugins.h"
 #include "mozilla/StaticPrefs_privacy.h"
@@ -351,8 +352,6 @@
 
 #define NS_MAX_DOCUMENT_WRITE_DEPTH 20
 
-extern bool sDisablePrefetchHTTPSPref;
-
 mozilla::LazyLogModule gPageCacheLog("PageCache");
 
 namespace mozilla {
@@ -3495,7 +3494,8 @@ void Document::RemoveFromIdTable(Element* aElement, nsAtom* aId) {
 void Document::SetPrincipals(nsIPrincipal* aNewPrincipal,
                              nsIPrincipal* aNewStoragePrincipal) {
   MOZ_ASSERT(!!aNewPrincipal == !!aNewStoragePrincipal);
-  if (aNewPrincipal && mAllowDNSPrefetch && sDisablePrefetchHTTPSPref) {
+  if (aNewPrincipal && mAllowDNSPrefetch &&
+      StaticPrefs::network_dns_disablePrefetchFromHTTPS()) {
     nsCOMPtr<nsIURI> uri;
     aNewPrincipal->GetURI(getter_AddRefs(uri));
     if (!uri || uri->SchemeIs("https")) {
diff --git a/dom/html/nsHTMLDNSPrefetch.cpp b/dom/html/nsHTMLDNSPrefetch.cpp
index 1484f525dcc3..ef90e7efb25e 100644
--- a/dom/html/nsHTMLDNSPrefetch.cpp
+++ b/dom/html/nsHTMLDNSPrefetch.cpp
@@ -38,7 +38,6 @@ using namespace mozilla::dom;
 using namespace mozilla::net;
 
 static NS_DEFINE_CID(kDNSServiceCID, NS_DNSSERVICE_CID);
-bool sDisablePrefetchHTTPSPref;
 static bool sInitialized = false;
 static nsIDNSService* sDNSService = nullptr;
 static nsHTMLDNSPrefetch::nsDeferrals* sPrefetches = nullptr;
@@ -59,15 +58,8 @@ nsresult nsHTMLDNSPrefetch::Initialize() {
 
   sPrefetches->Activate();
 
-  Preferences::AddBoolVarCache(&sDisablePrefetchHTTPSPref,
-                               "network.dns.disablePrefetchFromHTTPS");
-
   Preferences::AddBoolVarCache(&sEsniEnabled, "network.security.esni.enabled");
 
-  // Default is false, so we need an explicit call to prime the cache.
-  sDisablePrefetchHTTPSPref =
-      Preferences::GetBool("network.dns.disablePrefetchFromHTTPS", true);
-
   sEsniEnabled = Preferences::GetBool("network.security.esni.enabled", false);
 
   NS_IF_RELEASE(sDNSService);
diff --git a/modules/libpref/init/StaticPrefList.yaml b/modules/libpref/init/StaticPrefList.yaml
index 483ad8057b03..be744738a9a6 100644
--- a/modules/libpref/init/StaticPrefList.yaml
+++ b/modules/libpref/init/StaticPrefList.yaml
@@ -5985,6 +5985,11 @@
   value: 0
   mirror: always
 
+- name: network.dns.disablePrefetchFromHTTPS
+  type: bool
+  value: true
+  mirror: always
+
 # Max time to shutdown the resolver threads
 - name: network.dns.resolver_shutdown_timeout_ms
   type: uint32_t